It is known that in order to eliminate wastage as far as possible, one seeks to make the best use of the width of strip material and that, when its width does not correspond substantially to one of the dimensions of a given type of blank to be produced, blanks of different dimensions are produced simultaneously by selecting a method of cutting such that a maximum width of the strip is utilised.
To this end, the strip is firstly cut longitudinally into a plurality of elemental strips, generally two or three in number, the width of which corresponds to one of the dimensions of the blanks to be produced, and then each elemental strip is cut transversely to the desired length in order to obtain the desired blanks.
This cutting up of the various elemental strips is effected by a number of cross cutting devices equal to the number of elemental strips and the operation of each of which is independent, since the various basic strips are rarely cut to the same length.
At present, each of the cutting devices, the number of which is equal to that of the elemental strips, is designed so as to be able to cut across the entire width of the main strip, and, if it is impossible to impart lateral movements to the main strip or elemental strips, it is necessary to place these various cross cutting devices one above the other, which results in a bulky arrangement and generally has the result of limiting them to two or three in number, which also limits the number of elemental strips to two, and consequently also limits the possibilities of obtaining the best use of the width of the main strip.
Another drawback of such an arrangement is its high cost as regards its capital outlay and running costs, if one takes into account the fact that only one of the cutting devices is intended to be used occasionally over its entire width, any other cutting device being used solely when the mainstrip has been sub-divided into a plurality of elemental strips, which in other words means that it is only ever used over a part of its width.